The present invention relates to the methods of down-modulating osteoclastogenesis activity, thereby inhibiting bone matrix erosion and thus preventing bone loss and treating bone diseases. The present invention also relates to peptides and peptide analogues which inhibit TNF binding to its cellular receptors, methods of designing similar peptides and peptide analogues, and methods of using such compounds to inhibit the biological activities of TNF particularly those activities relating to bone resorption, thereby antagonizing its undesirable clinical effects.
Osteoclasts are large multinuclear cells which function to erode bone matrix. They are related to macrophage and other cells that develop from monocyte cells. Like macrophage, osteoclasts are derived from haematopoietic progenitor cells.
Bone matrix erosion is a normal process which occurs in coordination with bone matrix formation, a process in which osteoblasts are involved. Essentially, osteoblasts erode bone matrix and tunnel into bone while osteoblasts follow, line the walls of the tunnel and form new bone matrix. Typically, in a normal adult, about 5-10% of bone is replaced by these processes annually.
Bone diseases such as osteoporosis and Paget""s disease are characterized by a loss of bone. Similarly, metastatic bone disease, rheumatoid arthritis, and periodontal bone disease are also characterized by bone loss. In many cases, bone loss leads to fractures in patients. In addition to pain and suffering, patients become physically impaired which often leads to complications having negative consequences on patient health and quality of life. Moreover, the economic costs attributable to these diseases are tremendous.
Receptors and ligands of the Tumor Necrosis Factor (TNF) family have recently been shown to play an essential part in the differentiation and activity of osteoclasts and therefore play a role in bone resorption. On the one hand, TNF-xcex1 is known to promote osteoclastogenesis, the generation of osteoclasts. On the other hand, a TNF-like molecule present on and/or secreted by osteoclasts and stromal cells, referred to interchangeably in the field and herein as xe2x80x9cReceptor activator of NF-xcexaB ligandxe2x80x9d, (RANKL), xe2x80x9cOsteoclast differentiation factorxe2x80x9d (ODF), xe2x80x9cOsteoprotegerin ligandxe2x80x9d (OPGL), and xe2x80x9cTNF-related activation-induced cytokinexe2x80x9d (TRANCE), interacts with a TNF-receptor-like molecule, referred to in the field and herein as xe2x80x9cReceptor activator of NF-xcexaB ligandxe2x80x9d, (RANK), which, present in the membranes of osteoclast precursors and mature osteoclasts, regulates osteoclastogenesis and the resorbing activity of mature osteoclasts. The utilization of TNF-xcex1 antagonists, such as a monoclonal antibodies, for therapeutic purposes, has proven difficult, however, because of immunity to the large molecule, and limited entry into some specialized compartments of the body. Suda, et al. (Endocrine Reviews 20(3):345-357, 1999), which is incorporated herein by reference, describe osteoclast differentiation and function. Filvaroff, E and R. Derynck (Curr. Biol. 8:R679-R682, 1998) which is incorporated herein by reference, refer to bone remodeling and a signaling system for osteoclast regulation.
Thus, there is a need for methods of regulating osteoclastogenesis and the resorbing activity of mature osteoclasts. There is also a need for methods of preventing bone loss and treating bone diseases.
The present invention relates to methods of inhibiting osteoclastogenesis and the resorbing activity of mature osteoclasts. According to the present invention, an amount of a TRANCE/RANK inhibitor effective to inhibit osteoclast bone erosion activity is administered to a patient.
The present invention relates to methods of treating patients who have diseases characterized by bone loss. According to the present invention, an amount of a TRANCE/RANK inhibitor effective to inhibit osteoclastogenesis is administered to a patient.
The present invention relates to pharmaceutical compositions which comprise a TRANCE/RANK inhibitor in an amount effective to inhibit osteoclastogenesis.
The present invention relates to methods of modulating dendritic cell maturation, T cell proliferation, and/or CD40 receptor systems in an individual comprising the step of administering to the individual an amount of a TRANCE/RANK inhibitor effective to modulate dendritic cell maturation, T cell proliferation, and/or CD40 receptor systems.
The present invention relates to the use of peptides and peptide analogues designed from a binding loop of a TNF-R superfamily member. In particular, it relates to the use of peptides and peptide analogues designed from three binding loops of TNF-R. More specifically, the invention relates to peptides and peptide analogues which inhibit activities relating to bone resorption.
Generally, compounds used in the present invention are cyclic peptides or peptide analogues which are modified at their termini with hydrophobic moieties. In embodiments wherein the compound is a peptide, the peptide corresponds in primary sequence to a binding loop of a member of the TNF-R superfamily or a portion thereof. In a preferred embodiment, the peptide used in the invention corresponds in primary sequence to a binding loop of TNF-R p55 or a portion thereof. In certain embodiments, one or more amino acid residues within the peptide are substituted with other amino acid residues. Typically, such amino acid substitutions are conservative, i.e.,the amino acid residues are replaced with other amino acid residues having similar physical and/or chemical properties. In embodiments wherein the compound is a peptide analogues, the analogues is obtained by replacing at least one amide linkage in the peptide with a substituted amide or an isostere of amide.
In an illustrative embodiment, a compound used in the invention has the following formula: 
wherein:
AC is a peptide of 3-18 amino acid residues which corresponds in primary sequence to a binding loop of a TNF-R superfamily member, and which may optionally contain one or more conservative amino acid substitutions, or an analogue thereof wherein at least one amide linkage is replaced with a substituted amide or an isostere of amide;
AB1 is a moiety having a first functional group capable of forming a covalent linkage with one terminus of AC, a second functional group capable of forming a covalent linkage with AB2 and a third functional group capable of forming a covalent linkage with AA1;
AB2 is a moiety having a first functional group capable of forming a covalent linkage with the second terminus of AC, a second functional group capable of forming a covalent linkage with AB1 and a third functional group capable of forming a covalent linkage with AA2;
AA1 is a moiety having hydrophobic properties and a functional group capable of forming a covalent linkage with the third functional group of AB1;
AA2 is a moiety having hydrophobic properties and a functional group capable of forming a covalent linkage with the third functional group of AB2;
xe2x80x9cxe2x95x90xe2x80x9d is a covalent linkage; and
xe2x80x9cxe2x89xa1xe2x80x9d is a covalent linkage.
In a preferred embodiment of the compounds of formula (I), AC is a peptide which corresponds in primary sequence to a binding loop of TNF-R p55 and which optionally may contain one or more conservative amino acid substitutions, or an analogue thereof. In a particularly preferred embodiment, the peptides and peptide analogues specifically inhibit osteoclastogenesis.